TRKH AND ITS HOMOLOG, TRKG, DETERMINE THE SPECIFICITY AND KINETICS OF CATION-TRANSPORT BY THE TRK SYSTEM OF ESCHERICHIA-COLI

Autor(en): SCHLOSSER, A
MELDORF, M
STUMPE, S
BAKKER, EP
EPSTEIN, W
Stichwörter: BACTERIOPHAGE-T7 RNA-POLYMERASE; EXPRESSION; GENETIC-ANALYSIS; MEMBRANE-PROTEIN; Microbiology; NUCLEOTIDE-SEQUENCE; POTASSIUM UPTAKE
Erscheinungsdatum: 1995
Herausgeber: AMER SOC MICROBIOLOGY
Journal: JOURNAL OF BACTERIOLOGY
Volumen: 177
Ausgabe: 7
Startseite: 1908
Seitenende: 1910
Zusammenfassung: 
The corrected sequence of the trkH gene of Escherichia coli predicts that the TrkH protein is a hydrophobic membrane protein of 483 amino acid residues, of which 41% are identical to those of the homologous and functionally analogous TrkG protein. These two proteins form the transmembrane component of the Trk system for the uptake of K+. Each protein alone is sufficient for high-level Trk activity. When Trk is assembled with the TrkG protein, Rb+ and K+ are transported with a K-m near or below 1 mM; however, the V-max for Rb+ is only about 7% of that for K+. When Trk is formed with TrkH, the affinities for both for K+ and Rb+ are somewhat lower, and the V-max for Rb+ is only 1% of that for K+ transport. The kinetics of transport in strains with wild-type alleles at trkG and at trkH suggest that both products participate in transport.
ISSN: 00219193
DOI: 10.1128/jb.177.7.1908-1910.1995

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